Studies will be directed toward finding - in human normal, hyperplastic, and neoplastic prostatic tissues and short-term explant cultures - the presence of viruses, their sub-components or their expressed functions with properties analogous to those of known oncogenic viruses of other species. To this end, we will employ modern qualitative and quantitative approaches of molecular biology, biochemistry and electron microscopy such as: molecular hybridization of cellular nucleic acids with viral RNA, detection in prostatic tissues of reverse transcriptase and - characteristic for tumor viruses - high molecular weight RNA, accompanied by ultrastructural and functional definitions of viral particles induced in prostatic explant cultures by halogenated pyrimidines. In addition, we will use highly purified human interferon to distinguish between classes of inducible viral particles as well as to determine its antiproliferative potential against prostatic cells. Our findings would have far-reaching implications for the etiology of human prostatic cancer and for new practical approaches toward the prevention and possible treatment of neoplastic diseases in man.